This is where I am, as well. I get a delayed splash regarding the trail, but then the process dies. I've done the sign out/in, alt/shift start, deleted SLCache - all to no avail. When I do the alt/shift start, I do occasionally get the pop-up asking if I want to delete LR preferences. Still dies immediately after the trial/license window.

The log in/ log out through the preferences pane in the CC desktop application is NOT working for many, many people, myself included. I have read numerous discussions on this forum over the last few days and there are multiple threads with users who cannot launch the application. It isn't a problem that is solved by correctly logging in and out of the CC desktop application. While it works for some it has not worked for others. There HAS to be another fix for this. Many of us have been unable to use LR CC from the moment we downloaded it.